This invention relates to a method of controlling insects in turfgrass, ornamental plants or food crops using an insecticidally effective amount of certain N'-substituted-N,N'-diacylhydrazines.
The search for compounds which have a combination of excellent insecticidal activity towards target insects and low toxicity towards non-target species is a continuing one because of factors such as the desire for compounds exhibiting greater activity, better selectivity, lower undesirable environmental impact, lack of phytotoxicity to the locus of application, lower production and market cost and higher effectiveness against insects resistant to many known insecticides. In particular, there exists a need for effective control of Coleopteran larvae (grubs) in turfgrass, ornamental plants and food crops. Commercial insecticides, for example chlorpyrifos, carbaryl, acephate, isofenphos, isazophos, diazinon, ethoprop and bendiocarb, have serious deficiencies such as requiring a high application rate to be effective, possessing undesirable mammalian/arian toxicity, having poor soil mobility, and/or being toxic to beneficial soil animals such as spiders, ants and earthworms.
Although the economic value of the turfgrass industry is difficult to estimate, primarily because much turfgrass acreage is not grown for sale, turfgrass culture in its entirety as an industry contributes significantly to the economy. In the United States, for example, the production, service and maintenance of turfgrass amounts to billions of dollars annually. Protection of existing turfgrass plantings from various pests, including insects, is thus an important concern.
Coleopteran pests are widespread in their habitat. The northern masked chafer, Cyclocephala borealis Arrow, and the southern masked chafer, C. immaculata (Olivier), are native to the United States and are distributed over a wide area east of the Rocky Mountains. May or June beetles, both Phyllophaga spp. Harris, and the oriental beetle, Anomala orientalis Waterhouse, occur throughout Canada and the United States, particularly the eastern half of the United States. The European chafer, Rhizotrogus (Amphimallon) majalis (Razoumowsky), is most problematic in the northeastern United States and in Canada. The cupreous chafer, Anomala cuprea, is a particular problem for crops and turfgrass in Japan.
In the grub stage, the Japanese beetle, Popillia japonica Newman, is undoubtedly the single most important turfgrass-infesting member of the order Coleoptera in the United States. The grub is a major turfgrass pest of golf courses, recreational and industrial parks, school grounds and home lawns. Additionally, it is a major pest as an adult when it feeds on about 300 species of plants, including fruits, vegetables, ornamentals, field and forage crops, and weeds. The beetle's appetite for many ornamental plants greatly increases its pest status in landscape settings. It has a wide geographic distribution in the Northeast and the Midwest of the United States and in Ontario and Quebec in Canada where climatic conditions and large areas of permanent turf favor its development. Popillia japonica is is also a pest in Japan where it attacks highland crops and golf course turfgrass.
It is, therefore, an object of the present invention to provide an effective method for controlling insects in turfgrass, ornamental plants or food crops using an insecticidally effective amount of certain N'-substituted-N,N'-diacylhydrazines which have unexpectedly high activity against such pests. Because of this unexpectedly high activity, relatively low application rates of these compounds may be employed while control of the pests is maintained. These relatively low application rates, together with the relatively low mammalian toxicity levels possessed by the compounds of the present invention, result in reduced impact on the environment and reduced risk to the applicator, as well as a lower cost of application. Furthermore, by controlling the larvae or grub in the turfgrass or soil environment, a reduction occurs in the subsequent number of adult insects that feed on foliage, flowers, fruits and vegetables above ground.
U.S. Pat. Nos. 4,985,461 and 5,117,057 describe N'-substituted-N,N'-diacylhydrazines which are useful as insecticides, compositions containing those compounds and methods of their use. However, U.S. Pat. Nos. 4,985,461 and 5,117,057 do not teach or suggest which of these N'-substituted-N,N'-diacylhydrazines are effective for control of insects in turfgrass.